perlpodstyle

NAME

perlpodstyle - Perl POD style guide

DESCRIPTION

These are general guidelines for how to write POD documentation for Perl
scripts and modules, based on general guidelines for writing good UNIX man
pages. All of these guidelines are, of course, optional, but following
them will make your documentation more consistent with other documentation
on the system.

The name of the program being documented is conventionally written in bold
(using B<>) wherever it occurs, as are all program options.
Arguments should be written in italics (I<>). Function names are
traditionally written in italics; if you write a function as function(),
Pod::Man will take care of this for you. Literal code or commands should
be in C<>. References to other man pages should be in the form
manpage(section)
or L<manpage(section)>
, and Pod::Man will
automatically format those appropriately. The second form, with
L<>, is used to request that a POD formatter make a link to the
man page if possible. As an exception, one normally omits the section
when referring to module documentation since it's not clear what section
module documentation will be in; use L<Module::Name>
for module
references instead.

References to other programs or functions are normally in the form of man
page references so that cross-referencing tools can provide the user with
links and the like. It's possible to overdo this, though, so be careful not
to clutter your documentation with too much markup. References to other
programs that are not given as man page references should be enclosed in
B<>.

The major headers should be set out using a =head1
directive, and are
historically written in the rather startling ALL UPPER CASE format; this
is not mandatory, but it's strongly recommended so that sections have
consistent naming across different software packages. Minor headers may
be included using =head2
, and are typically in mixed case.

The standard sections of a manual page are:

NAME

Mandatory section; should be a comma-separated list of programs or
functions documented by this POD page, such as:

Manual page indexers are often extremely picky about the format of this
section, so don't put anything in it except this line. Every program or
function documented by this POD page should be listed, separated by a
comma and a space. For a Perl module, just give the module name. A
single dash, and only a single dash, should separate the list of programs
or functions from the description. Do not use any markup such as
C<> or B<> anywhere in this line. Functions should not be
qualified with ()
or the like. The description should ideally fit on a
single line, even if a man program replaces the dash with a few tabs.

SYNOPSIS

A short usage summary for programs and functions. This section is
mandatory for section 3 pages. For Perl module documentation, it's
usually convenient to have the contents of this section be a verbatim
block showing some (brief) examples of typical ways the module is used.

DESCRIPTION

Extended description and discussion of the program or functions, or the
body of the documentation for man pages that document something else. If
particularly long, it's a good idea to break this up into subsections
=head2
directives like:

=head2NormalUsage

=head2AdvancedFeatures

=head2WritingConfigurationFiles

or whatever is appropriate for your documentation.

For a module, this is generally where the documentation of the interfaces
provided by the module goes, usually in the form of a list with an
=item
for each interface. Depending on how many interfaces there are,
you may want to put that documentation in separate METHODS, FUNCTIONS,
CLASS METHODS, or INSTANCE METHODS sections instead and save the
DESCRIPTION section for an overview.

OPTIONS

Detailed description of each of the command-line options taken by the
program. This should be separate from the description for the use of
parsers like Pod::Usage. This is normally presented as a list, with
each option as a separate =item
. The specific option string should be
enclosed in B<>. Any values that the option takes should be
enclosed in I<>. For example, the section for the option
--section=manext would be introduced with:

=itemB<--section>=I<manext>

Synonymous options (like both the short and long forms) are separated by a
comma and a space on the same =item
line, or optionally listed as their
own item with a reference to the canonical name. For example, since
--section can also be written as -s, the above would be:

=item B<-s> I<manext>, B<--section>=I<manext>

Writing the short option first is recommended because it's easier to read.
The long option is long enough to draw the eye to it anyway and the short
option can otherwise get lost in visual noise.

RETURN VALUE

What the program or function returns, if successful. This section can be
omitted for programs whose precise exit codes aren't important, provided
they return 0 on success and non-zero on failure as is standard. It
should always be present for functions. For modules, it may be useful to
summarize return values from the module interface here, or it may be more
useful to discuss return values separately in the documentation of each
function or method the module provides.

ERRORS

Exceptions, error return codes, exit statuses, and errno settings.
Typically used for function or module documentation; program documentation
uses DIAGNOSTICS instead. The general rule of thumb is that errors
printed to STDOUT
or STDERR
and intended for the end user are
documented in DIAGNOSTICS while errors passed internal to the calling
program and intended for other programmers are documented in ERRORS. When
documenting a function that sets errno, a full list of the possible errno
values should be given here.

DIAGNOSTICS

All possible messages the program can print out and what they mean. You
may wish to follow the same documentation style as the Perl documentation;
see perldiag(1) for more details (and look at the POD source as well).

If applicable, please include details on what the user should do to
correct the error; documenting an error as indicating "the input buffer is
too small" without telling the user how to increase the size of the input
buffer (or at least telling them that it isn't possible) aren't very
useful.

EXAMPLES

Give some example uses of the program or function. Don't skimp; users
often find this the most useful part of the documentation. The examples
are generally given as verbatim paragraphs.

Don't just present an example without explaining what it does. Adding a
short paragraph saying what the example will do can increase the value of
the example immensely.

ENVIRONMENT

Environment variables that the program cares about, normally presented as
a list using =over
, =item
, and =back
. For example:

=over 6

=item HOME

Used to determine the user's home directory. F<.foorc> in this

directory is read for configuration details, if it exists.

=back

Since environment variables are normally in all uppercase, no additional
special formatting is generally needed; they're glaring enough as it is.

FILES

All files used by the program or function, normally presented as a list,
and what it uses them for. File names should be enclosed in F<>.
It's particularly important to document files that will be potentially
modified.

CAVEATS

Things to take special care with, sometimes called WARNINGS.

BUGS

Things that are broken or just don't work quite right.

RESTRICTIONS

Bugs you don't plan to fix. :-)

NOTES

Miscellaneous commentary.

AUTHOR

Who wrote it (use AUTHORS for multiple people). It's a good idea to
include your current e-mail address (or some e-mail address to which bug
reports should be sent) or some other contact information so that users
have a way of contacting you. Remember that program documentation tends
to roam the wild for far longer than you expect and pick a contact method
that's likely to last.

HISTORY

Programs derived from other sources sometimes have this. Some people keep
a modification log here, but that usually gets long and is normally better
maintained in a separate file.

COPYRIGHT AND LICENSE

For copyright

CopyrightYEAR(s) YOUR NAME(s)

(No, (C) is not needed. No, "all rights reserved" is not needed.)

For licensing the easiest way is to use the same licensing as Perl itself:

This library is free software; you may redistribute it and/or modify

it under the same terms as Perl itself.

This makes it easy for people to use your module with Perl. Note that
this licensing example is neither an endorsement or a requirement, you are
of course free to choose any licensing.

SEE ALSO

Other man pages to check out, like man(1), man(7), makewhatis(8), or
catman(8). Normally a simple list of man pages separated by commas, or a
paragraph giving the name of a reference work. Man page references, if
they use the standard name(section)
form, don't have to be enclosed in
L<> (although it's recommended), but other things in this section
probably should be when appropriate.

If the package has a mailing list, include a URL or subscription
instructions here.

If the package has a web site, include a URL here.

Documentation of object-oriented libraries or modules may want to use
CONSTRUCTORS and METHODS sections, or CLASS METHODS and INSTANCE METHODS
sections, for detailed documentation of the parts of the library and save
the DESCRIPTION section for an overview. Large modules with a function
interface may want to use FUNCTIONS for similar reasons. Some people use
OVERVIEW to summarize the description if it's quite long.

Section ordering varies, although NAME must always be the first section
(you'll break some man page systems otherwise), and NAME, SYNOPSIS,
DESCRIPTION, and OPTIONS generally always occur first and in that order if
present. In general, SEE ALSO, AUTHOR, and similar material should be
left for last. Some systems also move WARNINGS and NOTES to last. The
order given above should be reasonable for most purposes.

Some systems use CONFORMING TO to note conformance to relevant standards
and MT-LEVEL to note safeness for use in threaded programs or signal
handlers. These headings are primarily useful when documenting parts of a
C library.

Finally, as a general note, try not to use an excessive amount of markup.
As documented here and in Pod::Man, you can safely leave Perl
variables, function names, man page references, and the like unadorned by
markup and the POD translators will figure it out for you. This makes it
much easier to later edit the documentation. Note that many existing
translators will do the wrong thing with e-mail addresses when wrapped in
L<>, so don't do that.

SEE ALSO

For additional information that may be more accurate for your specific
system, see either man(5) or man(7) depending on your system manual
section numbering conventions.